Future communication systems are expected to, in many situations, be based on ad-hoc networks instead of, or in combination with, today's cellular communication approach with a central node, to which every device within reach of the central node should transmit the data. The development within wireless networking is going towards solutions where different radio access technologies, RAT, are supposed to be more and more integrated. As an example, capillary networks are already today used to connect sensors, meaning that within an area there are several sensors or devices connected with each other, typically using a Radio Access Technology utilizing unlicensed spectrum like Bluetooth or WLAN. One or several of the sensors or devices may also be connected to one or a few nodes that act as gateways to other networks or to the internet. In an example implementation, the communication to other networks or to the internet is made over another Radio Access Technology used in licensed band (LTE for instance), then the gateway or relay nodes are devices having cellular communication capabilities.
In addition, the amount of data transmitted over wireless networks is constantly increasing. Machine to machine, M2M, communication over mobile and wireless networks is expected to become increasingly important in the future. An M2M device may be mounted at places with severely low accessibility in tough environments limiting occasion for battery exchanges and re-charging. Hence, the need to save power is still highly relevant.
There is prior art disclosing methods for addressing power consumption in ad hoc networks. For example European Patent EP1573976 B1 discloses a method which also makes sure that no single node gets used too often and thus gets its battery drained. However, this solution is related to smoothing the power rather than minimizing the power usage.
There are also routing protocols directed to providing solutions for “routing” in ad hoc or mesh networks. For example, published European patent application EP 2 323 440 A1 takes into account the power consumption for each route when selecting a route in a meshed network.
However, these solutions are not optimised for devices capable of communicating over several radio access technologies in an environment with several integrated communication technologies. Hence, there is still a need for further simple transmission methods and strategies for transmitting a data packet between devices in a wireless network.